This invention relates to an application system and, more particularly, to an improved applicator head assembly for applying a strip of elastomeric material about a roller, mandrel, wire, cable and other similarly shaped cores.
Various types of products call for the use of a material strip wound about a cylindrical core. Such cores can include mandrels, rollers, pipe and other similarly shaped materials. Roller covering equipment, known as strip builders, are utilized which provide a method for winding a strip of elastomeric material about a rotating roller. Basically, the apparatus includes a traveling extruder for forming a strip of the elastomeric material. The extruder is mounted on a traveling platform that moves along the length of the rotating core. As the core rotates, the strip is wrapped about the core, such strip being pressed thereon by a head which concurrently travels along the length of the core. This process continues until a desired thickness of the material is wound about the core. Once achieved, the core is then heat treated, cured and precision machined such that a smooth elastomeric surface is presented about the core.
An effective application of the strip of the elastomeric material onto the roller core is desired. This elastomer could be thermoplastic or thermoset in nature and could be rubber or plastic. Thus, much interest has been directed to the design of an efficient applicator head that avoids the problems arising in the prior art. For example, heat build up problems have arisen due to the highly heated strip (400° F.) which is to be wound about the rotating core. Also, the strip of elastomeric material may stretch and/or sag between the extruder and the roller. Thus, the ability to effectively regulate the conveyance of the strip between the extruder and the roller core is of importance.
Accordingly, in response thereto, we have invented a novel applicator head assembly for use in a strip builder system. The head assembly comprises a stitching roller, an applicator head roller, a belt roller and a strip conveyor belt wound about the applicator and belt rollers. Upon rotation of the core, e.g., a mandrel, the contacting applicator roller rotates, which in turn rotates the belt roller due to a drive belt extending therebetween. Concurrently, a conveyor belt extending from an upstream extruder and about the downstream belt roller is driven into a gap between the applicator and belt rollers. As such, the elastomeric strip is deposited from the belt onto the adjacent downstream applicator roller. The rotating applicator roller then deposits the strip onto the adjacent rotating core. A stitching roller, as driven by the rotating core, smoothes the overlap of the elastomeric strip being wound about the core. The relationships among the belt roller, applicator roller and stitching roller can be adjusted according to the size of the rotating core so as to enhance the strip build up process. Accordingly, we have found that our assembly effectively addresses the prior heat build up and strip sagging problems and affords effective advantages in the strip build up process.
It is therefore a general object of this invention to provide an improved apparatus for deposit of a strip of material about a rotating core.
Another object of this invention is to provide an apparatus, as aforesaid, which includes an improved applicator head assembly for enhancing the transfer of the strip from an upstream extruder onto the downstream rotatable core.
A further object of this invention is to provide an apparatus, as aforesaid, which includes a belt roller, a conveyor belt and applicator roller, the conveyor belt being driven by the downstream applicator roller in contact with the rotating core.
Still a further object of this invention is to provide apparatus, as aforesaid, which effectively transfers the strip from the upstream conveyor belt onto a downstream applicator roller to prevent heat build up and sagging problems.
Another object of this invention is to provide apparatus, as aforesaid, which includes a stitching roller for smoothing the strip about the rotating core, the angle between the stitching and applicator rollers being adjustable.
A further object of this invention is to provide an apparatus, as aforesaid, wherein the relationship of the stitching and applicator rollers, relative to the rotating core, can be adjusted in response to the size of the rotating core.
Still another object of this invention is to provide an apparatus, as aforesaid, presenting structure allowing for an equal distribution of pressure by the applicator and stitching rollers onto the rotating core.
Another object of the invention is to provide apparatus, as aforesaid, wherein the surface speed of core rotation regulates the rate of transfer of the strip onto the rotating core.
Another object of the invention is to provide a regulated ratio between the surface speed of the applicator roller and the surface speed of the conveyor belt roller and belt therearound to preclude gaps or wrinkles in the elastomer strip prior to application.
Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, a now preferred embodiment of this invention.